By Tyler Saxton and Terry GilesYou’ve heard of Minecraft, Subway Surfers, Crossy Road, and Clash of Clans. But have you ever wondered why these apps are so popular.Bob Tedeschi, a reporter for the New York Times, explores this question every day because he writes about new apps! App creators send Bob their apps for him to try out and write a review of the app. He also created his own app Bobo Explores Light. In Bob’s experience, “only 5% of apps are actually good.” A good app includes a “central theme or character, levels and a mission and good graphics,” according to Bob. It took three months and three people to make the “Bob Explores Light” app, which was featured as an App of the Week by Apple.In the app students learn about all kinds of light. The interactive app uses Bobo, the robot, to explore science topics such as reflection, lasers, photosynthesis.Students can select a topic from a table of contents. Then, following Bobo, students learn facts on their topic, watch video clips , and have the opportunity to apply the learning with Bobo.“My favorite part was getting to show the app to my own kids” said Bob. He also likes to hear kids talk about how much they enjoy the app.The app has been used more and more in classrooms, which Bob also finds exciting.Bob made the decision to create the app because his editor made the suggestion. Bob said he was excited but also nervous because a lot goes into making the app. They had to research each of the topics in the app and how to create an app. Then he and his partners created their character. The hardest part was “killing off parts because the app was getting too big,” said Bob.The app can be found in the App Store for $5.